- WHAT IS RITONAVIR?
- WHO SHOULD TAKE IT?
- WHAT ABOUT DRUG RESISTANCE?
- HOW IS IT TAKEN?
- WHAT ARE THE SIDE EFFECTS?
- HOW DOES IT REACT WITH OTHER DRUGS?
|
this Fact Sheet on a single page using: |
|
|
|
|
|
More information on Downloading & Printing Fact Sheets |
|
PrintRitonavir is a drug used for antiviral therapy. It is also
called Norvir®. It is manufactured by Abbott Laboratories.
Ritonavir is a protease inhibitor. These drugs prevent the protease
enzyme from working. HIV protease acts like a chemical scissors.
It cuts the raw material for HIV into specific pieces needed to
build a new virus. Protease inhibitors “gum up” these
scissors.
IT?
Ritonavir was approved as an antiviral drug for people with
HIV infection. There are no absolute rules about when to start
antiviral drugs. You and your doctor should consider your T-cell count, your viral
load, any symptoms you are having, and your attitude about
taking HIV medications. Fact Sheet
411 has more information about guidelines
for the use of antiviral medications.
If you take ritonavir with other antiviral drugs, you can reduce
your viral load to extremely low levels, and increase your T-cell
counts. This should mean staying healthier longer.
Ritonavir makes the liver work more slowly. This can increase
the blood levels of some drugs, including other protease inhibitors.
Some doctors combine ritonavir with other protease inhibitors
to produce better blood levels.
RESISTANCE?
Many new copies of HIV are mutations. They are slightly different
from the original virus. Some mutations can keep multiplying even
when you are taking an antiviral drug. When this happens, the
drug will stop working. This is called “developing resistance”
to the drug. See Fact Sheet 414 for more information on resistance.
Sometimes, if your virus develops resistance to one drug, it
will also have resistance to other antiviral drugs. This is called
“cross-resistance”.
Resistance can develop quickly. It is very important to
take antiviral medications according to instructions, on schedule,
and not to skip or reduce doses.
HOW
IS IT TAKEN?
Ritonavir is taken by mouth as a liquid or capsule. The normal
dose is 600 milligrams (mg) twice a day. The capsules are 100mg,
so you will take 6 capsules every 12 hours. Ritonavir should be
taken with meals, if possible.
Ritonavir is sometimes combined with other protease inhibitors.
Different doses are used in some combinations. Be sure you know
how much ritonavir your doctor has prescribed for you, and when
and how to take each dose.
During 1998, there were problems with the original ritonavir
capsules. Production was stopped. Everyone taking ritonavir had
to take the liquid form. Many people think the liquid version
tastes bad. However, some people find the liquid more convenient.
It is still available.
Liquid ritonavir comes with a measuring cup. It takes 7.5mL
(milliliters) of liquid (1-1/2 teaspoons) to equal the normal
dose of 600 mg. The liquid version should not be refrigerated.
Shake the bottle before taking each dose.
Your pharmacist must keep the new ritonavir soft-gel capsules
refrigerated. You should keep ritonavir in your refrigerator,
but it can also stay out at room temperature (below 77 degrees
F, or 25 degrees C) for up to 30 days.
SIDE EFFECTS?
The most serious side effects are nausea, vomiting, gas, and
diarrhea. Some people also experience tingling or numbness around
the mouth, or find that foods taste strange. Side effects made
about one-third of people stop taking ritonavir in some clinical
trials.
For many people, the side effects of ritonavir lasted only
2 to 4 weeks. If they lasted beyond 4 weeks, in most cases they
were permanent.
To reduce stomach upset with ritonavir, start with half the
usual dose. Increase the drug on the following schedule:
Day 1: 300mg every 12 hours
Days 2-3: 400mg every 12 hours
Day 4: 500mg every 12 hours
Day 5 and after: 600mg every 12 hours
HOW
DOES RITONAVIR REACT WITH OTHER DRUGS?
Ritonavir is broken down by the liver. It can interact with
other drugs that use the liver. Combining these drugs can change
the amount of each drug in your bloodstream and cause an under-
or overdose. Drugs to watch out for include Viagra, several antihistamines,
sedatives, drugs to lower cholesterol and anti-fungal drugs. Make
sure that your doctor knows about ALL drugs you are taking.
If you are taking ritonavir and ddI,
you should take them 2-1/2 half hours apart.
Some birth control pills may not work if you are taking ritonavir.
Talk to your doctor about how to prevent an unwanted pregnancy.
The herb St. John’s Wort (See
Fact Sheet 729) lowers the blood levels of some protease inhibitors.
Tell your doctor about any herbs or other supplements that you
use.
Revised August
16, 2002
Goto InfoNet Main Page
Go toIndex of Fact Sheets
Clickhere if you have questions
New Mexico AIDS Education and Training Center
and the New Mexico Department of Health